Motorized fitness wheel

The present invention relates to wheeled exercise devices, and more particularly to electric motor assisted wheeled exercise devices used to achieve core and upper-body workouts.

Wheel-based exercise devices (also referred to as fitness wheels, exercise wheels, or abdominal exercisers) are often used to achieve core and upper-body workouts. Such devices typically consist of a wheel having a diameter of about six to eight inches mounted in the center of a shaft, with static handles extending axially from both sides of the wheel. The user grasps the device by the handles and rolls the wheel back and forth along the floor or other exercising surface.

Different types of wheel-based exercise devices are best categorized by their internal mechanisms, which ultimately influence the exercise experience.

The most common internal mechanism is simply a wheel-bearing-shaft assembly, favored for mass-production. Since users are restricted to exercising by resisting their own body weight, most beginners cannot complete even a single exercise repetition, and it is frustrating to get started. Meanwhile, advanced users find it difficult to get a sufficient workout, so they need to compensate by doing many high-repetition sets. The existing “abdominal exercisers” do little to correct these problems. Internal mechanisms that provide assistance and/or resistance to the user include bungee-assisted mechanisms, pneumatic mechanisms, spring-assisted mechanisms, and motors.

The bungee-assisted mechanism is a crude solution to the above issues, as it employs elastic cords, bands, or straps to give assistance (Note: In marketing materials these are often called “resistance bands” but the function is to assist (not “resist”) the user in pulling the wheel back; for the purpose of this patent, we call a force that pushes against the forward motion “assistance”). The bungee solution sacrifices portability and usability by requiring more equipment, especially if the user intends to vary their assistance as they progress over time. The bungee cord solution is very limiting in the types and amount of assistance it provides. Aside from functional disadvantages, the bungee cords can pose a significant safety issue if the user misassembles the product or slips and releases the handles. If the user reasonably decides to bail out during the exercise, a large amount of stored energy in the bungee cords may be expelled dangerously towards the user.

Pneumatic mechanisms change tire pressure to change the effective friction between the wheel and the ground, thus resisting inertia during the exercise. The pneumatic solution, however, only offers resistance over a limited range and can only provide a constant amount of difficulty throughout each repetition of exercise.

The spring-assisted mechanism uses an internal torsional spring at the center of the wheel to provide assistance. However, the user is limited in the amount of received assistance due to the material properties that define the internal spring. The geometry of torsional springs also restricts the mechanism to roll in one direction from the resting position of the exercise. As a result, only beginners benefit from the assistive properties of the mechanism; experienced users are unable to make their workout more difficult than the standard, bearing wheel.

Motors have been used to evolve fitness wheels beyond spring-assisted mechanisms. Motor-driven, geared fitness wheels with manual speed-control have been developed. Some motor-assisted devices attempt to back-drive the motor to generate electricity as a means of providing exercise. Supplementary to the features above, motor control has been adjusted to provide a resistance against the user on the rollback of the exercise, increasing the exercise difficulty for more experienced users. The motorized fitness wheel devices in the prior art have not had commercial success because they use basic motor control methods (e.g. constant speed control), resulting in a sub-par exercise experience for the user. None of the existing motor-assisted fitness wheels specifies dynamic or real-time control of the motor: characteristics of the present invention that increase accessibility and promote exercise progression (i.e., increasing difficulty over time). The existing motor-assisted fitness wheels also lack effective and practical safety mechanisms which would prevent the motor from running when the exercise is aborted. Lastly, the existing motor-assisted fitness wheels do not have intuitive, engaging user interfaces.

It is with respect to these and other considerations that the disclosure made herein is presented.

According to an aspect of the present disclosure, a motorized exercise wheel is provided for performing an exercise having at least one cycle in which a user rolls the wheeled mechanism (we will refer to it as a “wheel” understanding that it may have more than one wheel) along a surface in a forward direction from an approximate resting position to an extended position and then rolls the wheel along the surface in a backward direction from the extended position toward the resting position. The motorized exercise wheel comprises a wheel assembly including a ground-contacting element, the ground-contacting element being configured to contact the surface and rotate about an axle in either a forward rotational direction and a backward rotational direction and thereby roll along the ground in either the forward or backward directions. The motorized exercise wheel also comprises a first and second handle configured to receive each hand of a user, the first and second handle extending outward from respective sides of the wheel assembly. The motorized exercise wheel also comprises a motor coupled to the wheel assembly and configured to apply an output torque to the ground-contacting element in either the forward rotational direction or the backward rotational direction. The motorized exercise wheel also comprises a microcontroller comprising one or more processors and being configured to control an output torque of the motor. The motorized exercise wheel also includes a sensor in communication with the microcontroller and configured to determine a movement variable of the exercise wheel. The motorized exercise wheel also comprises a non-transitory computer readable storage medium accessible by the microcontroller. Additionally, the microcontroller is further configured to control the output torque of the motor over the exercise cycle as a function of the determined movement variable.

According to a further aspect a method of operating a motorized exercise wheel for performing an exercise is disclosed. The exercise involves at least one cycle in which a user rolls the wheel along a surface in a forward direction from an approximate resting position to an extended position and then rolls the wheel along the surface in a backward direction from the extended position toward the resting position, thus forming the cycle. The wheel includes a wheel assembly including a ground contacting element, an electric motor coupled to the wheel assembly, first and second handles extending from the wheel assembly for handling by the user and a microcontroller. The method, which is performed by the microcontroller, comprises a step of determining, using a sensor, a movement variable concerning movement of the exercise wheel during the exercise, the movement variable being determined with the sensor throughout the at least one cycle. The method also includes determining, a target output torque for the motor based at least in part on the movement variable determinations. The method also includes controlling an output torque of the motor over the exercise cycle as a function of the target output torque.

These and other aspects, features, and advantages can be appreciated from the accompanying description of certain embodiments of the invention and the accompanying drawing figures and claims.

It is noted that the drawings are illustrative and are not necessarily to scale.

By way of overview and introduction, the systems and methods disclosed herein concern a motorized fitness wheel.is a perspective view of an exemplary fitness wheelaccording to an embodiment.is a cross-sectional view of the fitness wheeltaken along line A-A shown insuch that the top half of the fitness wheel has been cut-away to reveal internal components of the fitness wheel.

As shown in, the hardware of the fitness wheelcomprises of a motor, which is mounted inside of a wheel. At the interior radius of the motor lies a hearing assembly, configured to allow the motor to provide torque between the rotating portion of the wheeland a static axle shaftthat is coupled to the handles, The outer radius of the wheel includes a ground-contacting elementconfigured to roll along the ground. Handlesextend outward from each side of the wheel, generally along the rotational axis of the wheel, and are intended to be grasped by the user during use. The wheel is closed off by two hubcaps, the interior of which houses internal components including batteries, electronics, the motorand the like.

A user interface is provided on the outside of one of the hubcaps and comprises a physical interface including a rotatable difficulty selection rotary dial, Bluetooth button, and power button. The fitness wheelalso comprises visual indicators such as an exercise difficulty display, which displays the difficulty selected by the user using, the difficulty selection rotary dial. Visual indicators also include LEDs, which are used to provide feedback to the user in regard to exercise status and progress, making the exercise experience more engaging and enjoyable.

is a block diagram illustrating the interconnected and interoperating mechanical, electrical, and software components of the fitness wheel, configured to provide real-time, dynamic control of the motorized fitness wheel in response to user actions, according to an embodiment.is a block diagram showing an exemplary configuration of the electronics of the fitness wheel, according to an embodiment.

The fitness wheelprovides a unique advantage in that it can provide assistive exercises to beginners and resistive exercises to experts, maximizing the use of any athlete's available time and energy. The fitness wheelis configured such that users can interact with the device both physically, by providing inputs via a physical interface comprising electromechanical hardware (arrow) and digitally, by providing inputs via a digital interface (e.g., software application executed on a smart phone, tablet, personal computer, etc.) (arrow). Both types of inputs can be received and processed using a microcontrollerand used to define the type and the difficulty of exercise, often given by the user s strength, fitness, and/or experience level. For example, a user can select a difficulty level using the rotary difficulty selection rotary dial, which is received at the microcontroller(arrow). Similarly, the user can select a difficulty and/or an exercise type using a smartphone application, which is received at the microcontroller (arrow) via a wireless communication connection (e.g., Bluetooth). In response to the user inputs sent to the microcontroller onboard the fitness wheel, the microcontroller initiates a motor feedback loop (arrows numbered) as a function of the user inputs to control the operation of the fitness wheel and thereby facilitate the exercise. In an embodiment, the motor-feedback loop subsystem is configured to operate as follows: sensorsmeasure and relay real-time current data measured from the motor to the microcontroller; microcontrollercomputes the torque-generating portion of the current and identifies any discrepancy between measured and target torque-generating currents; microcontrollergenerates corrective information as a function of the discrepancy, which is sent as a new voltage command (as a duty cycle) to the motor electronicswhich drive the motor. As further described herein (see § 2.4.2), the “target” torque output is dependent on certain data, derived from the aforementioned user inputs, among other parameters. Simultaneously, a battery management loop (arrow) is provided to ensure that battery voltage is managed appropriately including indicating to the user when the battery needs charging. Alternatively, battery management electronicsmay control the battery without any additional software input from the microcontroller. In an embodiment, the battery, which can comprise a single or multiple battery units referred to herein simply as a “battery”, is managed by electronics: the microcontrollerreads the battery voltage for control, and the battery manager/electronicscharges the battery whenever it is plugged in for charging and the battery need to be charged. The battery supplies voltage and current to the electronics. As shown in, the microcontrollercan also be configured to output information to the digital interface of the user (arrow), for instance, via the on-board user interface including the rim-mounted LEDs, or via a physical interface (arrow) such as the difficulty display.

In an embodiment, the fitness wheelcomprises an outrunner motorin which the stator is the hub of the motor, and the rotor (the moving portion) is on the outside, surrounding the stator. The windings of the motor are connected to a motor drive (not shown) that energizes the motor. Although the illustrated embodiment ofshows a motordirectly coupled to the rotating portion of the wheel, this is exemplary and non-limiting as it should be understood that the motor can be coupled to the wheel through a suitable transmission (e.g., gears, belts, etc.).

In an embodiment, the physical user interface elementsare located on the hubcap, on one side of the fitness wheel. Various features and functionality of the fitness wheelare controlled by the microcontrolleras a function of user inputs provided using the physical tactile elements of the interface, including, the difficulty selection rotary dial, Bluetooth button, and power button. As would be understood, the Bluetooth button causes the fitness wheelto connect via a wireless communication interface (e.g., Bluetooth) to remote devices such as a user's smartphone. An exercise digital interface application can be running on the smartphone allowing the user to interact with the fitness wheelvia the smartphone.

In one embodiment, the microcontrolleris configured to display a value representing the selected exercise difficulty on the difficulty display. As shown, the difficulty displaycan comprise a range of numbers on the fitness wheel hubcap (displayed as: 5 4 3 2 1 0 1 2 3 4 5). For instance, when a difficulty is selected using the selection rotary dial, the selected number can be illuminated by the microcontroller in either red (to the left of zero, signifying hard difficulty) or green (to the right of zero, signifying easy difficulty). Although the power function can be automatically controlled via a software application, a mechanical power buttoncan be provided to give the user control and confidence of the status of the fitness wheel. In an embodiment, Bluetooth control buttonis provided as a separate button to avoid unwanted power cycling, instead of consolidating Bluetooth into the power button for dual functionality. In an embodiment, the Bluetooth button can be eliminated, relying on Bluetooth Low Energy (BLE) to allow portable devices to establish a connection to the fitness wheel. This feature would be particularly beneficial in a public gym, personal training or physical therapy facility because users could walk up to the fitness wheel and quickly establish communications with it.

Other elements of the interfacecan include: visual state communication devices (LEDson wheel rim), and haptic feedback (motor control signals causing motion that users can feel on the handles). Another interactive user interface element can include the exercise digital interface(i.e., the smartphone application) executing on the user's smartphone and configured to wirelessly send user inputs and control commands to the microcontroller.

The wheel rim mounted LEDscan be controlled by the microcontrollerto communicate information concerning different states of the wheel (e.g., low battery, completed repetition, Bluetooth connection status, etc.) to the user through different colors, patterns, and animations (see e.g., Table 1, below).

In an embodiment, the LEDsare specifically placed on the rim of the wheel to maximize their presence in the field of view of the user. In an embodiment, as further describe herein, the fitness wheel can be configured to provide haptic feedback via the “flutter” command (see § 2.4.2.4) to designate wheel states. In an embodiment, the smartphone applicationcan also be configured to operate in tandem with the fitness wheel as a digital interface to communicate exercise progress as well as health statistics in greater detail.

In an embodiment, two circuit boards contain the electronics on-board the fitness wheelfor controlling its operation. It is well understood that the two boards can be combined into one or split into more than two for any reason including improved packaging or cost reduction.

As shown in, and as explained above, in an embodiment, the microcontrollerreceives user inputs via the selection dial (arrow) and digital interface(arrow) and controls operation of the fitness wheel accordingly. Similarly, the microcontroller can be configured to output information relating to the operation of the fitness wheel via the LEDs(arrow) and digital interface(arrow).

The microcontroller, connected to the motor, is configured to control the motor torque during the exercise. Reference to “microcontroller” in this document can refer to either: a) a single microcontroller or microprocessor performing one or more of the functions; b) multiple microcontrollers or microprocessors performing various functions in unison or; c) a mix of microcontrollers or microprocessors performing various functions in unison. It should also be understood that reference to microcontroller can encompass other types of custom or preprogrammed logic device, circuit, or processor, such as a programmable logic controller (PLC), computer, software, or other circuit (e.g., ASIC, FPGA) configured by code or logic to carry out their assigned task.

As shown in, in an embodiment, the microcontrolleris part of a motor drive circuit identified by connections labeled. More specifically, a motor controller moduleof the microcontroller controls a 2 or 3-phase bridge, which controls voltages/currents provided to a brushed or brushless motor. A brushless motor can be preferred for smoother operation. The motor drive circuit also includes a feedback loop. As the user exercises with the fitness wheel, the feedback loop comprising a combination of sensors (e.g., hall sensors, magnetic sensors, current sensors, and an encoder) relays motor position and current data to the control microcontroller unit. In an embodiment, the feedback loop of the motor drive circuit can comprise current sensors with signal conditioning,. This feedback loop is put in place to ensure the motor is following the correct torque profile along the exercise path.

In the preferred embodiment, the electronics are powered by a batterythat is managed by battery management electronic components (,). In an embodiment microcontrollercomprises two microprocessor units, the motor controllerand a supervisor controller. The supervisor controllercommunicates with the motor controllerand peripheral devices including user interface devices among other electronic hardware components (e.g., LED driver, for driving the LEDs).

In an embodiment, the motor controllermanages control of the device's Brushless DC (BLDG) motor. In addition, the motor controller utilizes a gate drive and a 3-phase bridgeto control a brushless three-phase motor. The supervisorcontroller processes user-input from peripherals such as rotary dialsor inputs received over Bluetooth from the smartphone application. In some embodiments, the supervisor controllercommunicates with the motor controller over a bus (such as an SPI bus) which will communicate information such as requested state changes or exercise measurements. Note that this architecture is an example, however, many related alternatives are possible, for example, one MCU can be used for both motor control and user interface, and different motor types (induction, brushed DC, variable reluctance, etc.) can be used without departing from the scope of the disclosure.

To properly control the motor, one or more sensors (e.g., sensors,; sensors,,) can be used to collect information for the microcontrollerand its software concerning one or more movement variables. The information measured by the sensors and used by the microcontroller to control the motor can include positional information, which represent spatial and/or temporal variables concerning the movement of the fitness wheel(e.g., displacement, velocity, acceleration, and the like). For example, in an embodiment, position sensorcan comprise a rotary encoder used to measure the angle of the motor. In an embodiment, position sensorcan comprise a hall effect or magnetic sensor to measure the angle of the motor within a phase. From this position information, the motor's angle, speed (revolutions over time), and acceleration (e.g., rate of change of speed) can be computed by the motor controllerfor use in commutating the motor and controlling the exercise. It should be understood that, in addition or alternatively, hall effect sensors, magnetic sensors, or any other suitable positional feedback sensor can be used for this function. It should be understood that reference to a position sensor is not limited to a sensor device and can include an estimator configured to estimate a given variable based on other measured information. The information collected by the sensors and used to control the motor can also include motor output variables such as torque. Sensors usable for measuring torque output can include, for example, current sensors (e.g., sensors) configured to measure torque-producing current of the motor which is representative of the torque output.

In an embodiment, as shown in, the microcontroller, particularly the motor controller, can use pulse-width-modulation (PWM) peripherals to send switching commands to a three-phase inverter comprising three half-bridgesusing Field Effect Transistors (FETs, not shown). The inverter modulates the electrical voltages to the motor to control it.

In the motor feedback loop (connectionsofand connectionsof), software executing in the microcontroller, particularly, the motor controller, configures the microcontrollerto generate a “target” torque command (which might be expressed as a fraction of torque-producing current). The torque command controls the output torque of the motor drive, thus defining the exercise experience for the user. By defining torque as a function of certain variables (see § 2.4.2.2), the resulting characteristic motor responses serve to challenge the user to exercise in different ways.

In an embodiment, the output torque (τ) of a brushed DC motor drive can be expressed as follows:τ=,  Eqn. 1.1

where Iis the armature current and kis the torque constant (motor-dependent). In the case of vector control of a three-phase motor, Iis the torque producing component of the DQ-current (I). It is important to note that the magnitude of Iin Equation 1.1 is bounded, such that:τ,τ,  Eqn. 1.2.1-2

where Iis the maximum operating torque-producing current, dependent on the limitations of motor, electronics, and battery. Since the magnitude Imay not exceed Ior −I, Iwill always be a fraction of I, shown by the following relationship:

Defining torque-producing current in a nondimensionalized form (I*), and manipulating that variable, allows for increased utilization of the precision of the number representation used in Microcontroller/Software. By controlling the motor using a D-Q formulation [1], the motor controllercan command motor torque by commanding the Icomponent of the current (set I→I). The angular sensor (encoder, hall effect, or magnetic, etc.) is used to compute the D and Q directions and align the currents.

In an embodiment, the different algorithms for controlling the motorare organized to aid in the development and implementation of programmed exercises through selective combination of various algorithms. “Exercises” are most general and are defined by information such as (but not limited to):

These and other algorithms for controlling the motor can be stored in a non-transitory computer readable storage medium (not shown) that is accessible to the microcontroller to enable execution during use. In an embodiment, the digital interfacecan also be configured to store exercises, trajectories, profiles, events and other such motor control algorithms and provide selected algorithms to the microcontroller for local storage and implementation.

The user's form plays a critical role in dictating what muscle groups receive activity throughout the exercise, independent of trajectory and events. In an embodiment, training software matches the trajectory to a proposed user's form (movement) so the user can perform the recommended exercise (usually by doing “reps”).

Following is a discussion of user form and how form factors into the motor control.

For purposes of illustration, a computer simulation of the fitness wheeland user was used to generate a “tin man” exercise simulation and an animation depicted in. The representative body part lengths, masses and joint angles correspond to an actual human subject. Visual targets were mounted on a test subject while using the exercise wheel and the subject was recorded with a camera. The joint angles used in the simulation were obtained from analysis of a video of the human-subject performing the exercise.throughshow the position of the user in a 3-D animation created by performing a simulation of the exercise with the joint angles based on the above-mentioned video analysis. Also shown in dashed lines inare the paths of the user's hips and shoulders and the wheel center during the exercise.

If the fitness wheelis inactive, the muscle generated torques working at the subject's shoulder and hip, and wrist joints,,during exercise result mainly from resisting the pull of gravity. During exercise these torques vary with the user's form. Further, if the fitness wheel is active, the working torques appearing at the subject's joints can be altered by the fitness wheel. The fitness wheel can either assist or hinder (resist) the motion of the user.

Muscles can only generate tension in tendons, i.e., they can only pull. In the body, different muscles groups are arranged antagonistically to generate the positive and negative torques working at the subject's joints. Thus, when the sign of the torque changes from positive to negative, the predominate muscle groups being used change, e.g., from back muscles to abdominal muscles as the exercise starts.

The displacement (d) of the fitness wheel center during exercise is plotted in the. This plot can be used to correlate the position of the wheel (and the user's form) during the exercise.

As an example, the torques (τ) that the fitness wheel motor can apply to the wheel are plotted in. Specifically,illustrates torque applied by the simulated fitness wheel for three cases: (1) no-assist, 0 Nm (represented by a square), (2) maximum-assistance, −6 Nm (represented by a circle), (3) maximum-hinderance, +6 Nm (represented by a triangle). Note that the applied torque also appears, with opposite sign, as a torque at the user's wrists. Further, while the example shows a constant torque being applied, it should also be noted that, during exercise, the torque applied by the fitness wheelunder control of the microcontroller, can vary anywhere between the maximum-assistance and the maximum-hinderance values.

If the fitness wheelis inactive, the motor applies 0 N·m torque, otherwise the motor can apply anywhere between positive full torque and negative full torque. In an embodiment, the maximum torque is between 6 and 16 N·m. In the simulations shown herein, the maximum torque was chosen to be only 6 N·m, therefore the torques in the plots range from +6 N·m and −6 N·m torque, depending on programming. The applied torque of the motor results in an opposing reaction torque at the fitness wheel handgrips of −6 N·m and +6 N·m respectively. In addition to the reaction torque, a horizontal force is generated at the wheel-floor interface, e.g., Fx=(−6 N·m/Radius_of_wheel). The horizontal force also appears at the fitness wheel handgrips and acts on the subject.

Both the torque and the force at the fitness wheel handgrips alter the joint torque to be generated by the various muscle groups. Changing the radius of the wheel, changes the proportion between force and torque at the handgrip. A smaller radius gives a larger magnitude force for the same torque.